“Medtronic has already taken a number of concrete actions to enhance device security and is committed to implementing continual improvements.

“We continuously monitor the security of our devices and if new vulnerabilities are revealed, Medtronic will assess whether additional security measures can be implemented without compromising the therapy that the device is designed to deliver to patients.

“We believe the risk to an individual customer is low and the therapeutic benefits of our cardiac devices for treating heart conditions far outweigh this risk.”

Over the past decade, there's been an explosion of tiny networked devices that manage a variety of health maladies, from regulating the beating of the human heart to controlling serious diabetic conditions.

Allowing the devices to connect wirelessly to computers or other devices saves money, helps doctors to collect valuable data and can eliminate the number of operations needed to keep them in working order.

But it leaves them open to being disabled or sabotaged.

In the TV series Homeland, Damian Lewis was seen to give terrorists a serial number so they could hack the pacemaker of Vice-President William Walden.

It is thought the plot idea emerged after former US vice-president Dick Cheney had wireless reprogramming disabled on his implanted defibrillator to prevent hacking in 2007.

Now forensic medicine and security specialists are joining forces to develop software which can tell a pathologist if a pacemaker has been interfered with before death.

Sujeet Shenoi, a computer security engineer at the University of Tulsa in Oklahoma, told New Scientist: “The problem is that there has to be a way to access these very small, simple devices to reconfigure them, change their settings and patch the software.

“That means there are a nay number of ways to compromise them and their firmware.

“The medical device manufacturers are not working hard behind the scenes to stop this happening.”

To create software which monitors unusual activity, the researchers have drawn up a list of medical events that could lead to the death of a person with an implanted defibrillator – a device which helps the heart beat more rhythmically through a series of shocks.

They included sending a series of quick shocks to accelerate the heartbeat and cause a fatal arrhythmia or reprogramming the device so that it does not kick in when required.

A pathologist can then examine the defibrillator after death to see if any of the scenarios which could cause a lethal attack had taken place. If something untoward was spotted, an investigation could begin.

“That would be proof against everything but a malicious pathologist,” said Noureddine Boudriga, a cryptographer at the University of Carthage in Tunisia.

So far there has been no recorded case of death or injury because of a bodily cyber-attack. But without software to pick up irregularities, it is unlikely a coroner would have spotted an attack.

In June 2013, the DHS Industrial Control Systems Cyber Emergency Response Team (OCS-CERT) identified 300 medical devises made by 40 companies which had unchangeable passwords which could allow someone to login and change critical settings.

Researchers from MIT and the University of Massachusetts, Amherst, are also developing a ‘noise shield’ which could block out attacks.